Diacylglycerol has different nutritive values and physiochemical characteristics from triacylglycerol which is a major component of vegetable oil. Taking advantage of such characteristics, diacylglycerol has a wide range of prospective applications to edible oil, such as a salad oil, or chemical materials.
Heretofore, diacylglycerol has been produced from triacylglycerol obtained by compressing soybeans, rapeseeds or the like. These conventional methods include (1) a method based on an ester exchange reaction between oil and glycerol, and (2) a method based on an esterification reaction using fatty acid and glycerol. In these methods, either one of a chemical reaction using a catalyst of alkali (earth) metal hydroxide or an enzyme reaction has been used (see Japanese Patent Laid-Open Publication No. 2001-64671, WO 99/48378).
Such reactions have a disadvantage in terms of complicated production processes and/or relatively high cost because of (1) the need for a process of separating a desired product from by-products to purifying the desired product or (2) the needs for purified fatty acid as a material.